Bell construction for chair support



Oct. 22, 1968 1 F. DOERNER 3,406,939

BELL CONSTRUCTION FOR CHAIR SUPPORT Filed Dec. 16, 1966 I 26, I /5'J 28 3o 22 I 23 3O I? 56 36 INVENTOK H K 1105mm ATTORNEY United States Patent 3,406,939 BELL CONSTRUCTION FOR CHAIR SUPPORT Frank Doerner, Waterloo, Ontario, Canada, assignor to Doerner Products Co. Limited, Waterlo0,'Ontario, Canada, a corporation of Canada Filed Dec. 16, 1966, Ser. No. 602,312

6 Claims. (Cl. 248405) I ABSTRACT OF THE DISCLOSURE This invention relates to the construction ofheight-adjustment mechanisms for chair support.

To date, chairs of this type, in providing for vertical seat adjustment have employed a seat support post threadably engaged in a tapped malleable iron nut housed in an inverted bell-shaped housing which acts as an adjustinghandle.

The nut of the prior art devices includes an upwardly protruding boss which projects through an axially aligned bore in the upper face of the bell housing. The two last mentioned members are fixedly interconnected as, for eX ample, by swaging thewalls of the protruding boss into contact with the upper face of the housing and the periphery of the bore formed therein.

With further reference to the prior art structures, it is noted that the nuts are substantially smaller in lateral dimension than the diameters of the housings in which they are fitted. During shipping of the support structures, the seat posts are threadably engaged in the nuts and-it can happen that the impact of a blow on the post distorts the nut and housing assembly, tilting the nut in the housing with obvious detrimental results as regards subsequent adjustment of the assembled chair.

From the foregoing it will be obvious that there exists a definite need for an improved construction in this particular area of seat support design.

The present invention overcomes the prior art problems by providing a relatively inexpensive tapped stamping, force-fitted into the bell housing.

It is an object of the present invention to provide a simplified, less expensive and more efficient structure for effecting up and down adjustment of a chair seat relative to its base structure.

It is a further object of the invention to provide a height adjustment mechanism, of the type hereinabove mentioned, requiring no swaging or other similar type of interconnecting expedient between the elements of the combination.

A still further object of the invention resides in the provision of a height-adjustment mechanism constructed in such a manner that mis-alignment of interrelated parts is substantially impossible during transit or in normal use.

Further objects and advantages will become apparent from the following detailed description of two illustrative embodiments of the invention taken in conjunction with the appended drawings wherein:

FIG. 1 is a side elevation of a chair-type upon which the present invention can be used;

FIG. 2 is an exploded perspective view of a bell housing and a stampled nut, in accordance with one embodiment of the invention;

FIG. 3 is a partial, sectional view of the assembled mechanism of FIG. 2; and

FIG. 4 is a sectional elevation of a second embodiment of the invention.

FIG. 1 of the drawings illustrates a -chair'assembly generally designated by the numeral 10 and including a base or floor-contacting structure 12, a seat portion 14, aback portion 16 and a chair support post 18.

The seat portion114 is mounted on support post 18 for rotation therewith and the latter is mounted in the floorcontacting structure 12 for up and down movement as well as rotative movement relative thereto. This will be more 'fully described hereinbelow.

With particular reference to FIG. 2, One embodiment of the present inventive structure is disclosed consisting of an inverted cup-shaped bell housing 20 having an upper annular face 22. The bell-housing 20 provides a handle by means of which the height adjustment mechanism can be operated. Around the inner periphery of face 22 'depends an integral flange 24, provided to 'limit lateral movement of post 18 with respect of housing 20. This flange'should be deep enough to at least span adjacent crests of the threads on support post 18.

The annular face 22 and the flange 24 define an axially aligned bore through which the seat support post 18 projects into the floor-contacting structure 12.

A stamped nut 26 of mild steel is shown in both FIGS. 2 and 3. The nut 26 consists of a disk-shaped element having a central extrusion or boss portion 28 and an integral annular skirt 30 dimensioned to provide an interference fit with the internal diameter of bell housing 20. Since, in many cases, it is desirable to utilize a substantially deep bell housing in certain chair support designs, it is expedient to locate the nut 28 in spaced relation to the annular face 22. Naturally, if the housing 20 is of considerable depth, the press equipment required to drive the nut into contact with face 22 would be of such a length as to unnecessarily complicate insertion of the nut. In the interests of manufacturing expediency, whether the bell housing 20 is shallow or deep in respect of vertical extent, the nut 26 is always pressed into the housing to a depth A as indicated in FIGS. ,3 and 4.

Although the following form no part of the present invention, it should be noted that diametrically opposed, radially aligned slots are provided to register with guide rods on manufacturing equipment to facilitate threading and insertion of nut 26.

As shown in FIG. 2, the underside of skirt 30 is provided with a plurality of equispaced indentations 34 which are operable to coact with complementary detents on a thrust bearing 34a (see FIG. 3) and for the same purpose as that generally disclosed in applicants co-pending US. patent application Ser. No. 527,376 filed Feb. 14, 1966 and entitled Thrust Bearing for a Swivel Chair.

The thrust bearing 34a, as disclosed in the above indentified application is keyed to the support post and coacts with the indented nut to prevent relative rotation between the support post and the out when a load is applied on the chair seat. Thus, height adjustment of the chair seat can only be effected when no load is carried by the chair.

In the interests of clarity, FIG. 3 merely illustrates a novel assembly of hell housing 20 and stamped nut 26 located on a central cylindrical column 36 which forms the hub of the base or floor-contacting structure 12 of the chair. In the illustrated embodiment of FIG. 3, the load is transmitted from the seat portion, through the support post and nut 26, thence through the bearing 34a (schmetically indicated) directly to the base structure of the chair. It should be noted that no force is applied to the nut which would tend to move the latter relative to the bell housing..However, aplication of appropriate interference tolerances results in a housing-nut assembly which could, if necessary, accept a greater load than the chair design load without shifting or tilting of the nut in any way relative to the bell housing.

As is usual, a stud or screw 20:: is threadably inserted in a tapped hole 20b formed adjacent the lower edge of bell housing 20. The inner end of stud 20a contacts the outwardly turned flange 36a of column 36 to prevent inadvertent withdrawal of post 18 from the floor-contacting structure 12 when the chair is lifted, for any reason, by the seat or back portions thereof.

Turning to FIG. 4, a second embodiment of the invention is disclosed. In this second case, a bell housing of substantially minimum depth is illustrated and, in such cases, it is possible to press the nut 28' into the bell housing 20' until the upper surface of the annular skirt 30' abuts the inner surface of annular face 22' while maintaining the constant dimension indicated by letter A. As will be noted, in the second embodiment, there is no necessity to include the dependent flange 24 of the first embodiment. The tapped boss of nut 28' projects outwardly of the bell housing. By reason of the fact that the nut is force-fitted into the bell housing, no swaging of the nut projection is required to rigidly interconnect the nut and the housing. It is, of course, substantially impossible to tilt or otherwise move the nut 28' relative to the housing either during transit or in actual use.

What I claim is:

1. In a chair having a floor-contacting portion; a seat portion adjustably mounted on the floor-contacting portion by a threaded chair post; the improvement comprising:

(a) an inverted cup-shaped bell member including an upper annular face defining an axially aligned bore,

(b) a centrally tapped stamping press-fitted into fixed engagement within the bell member and supportable on said floor-contacting portion of the chair, whereby said chair post is projectable through the bore in the bell member face for threadable engagement with the said tapped stamping to permit up and down adjustment of the seat portion relative to the floor contacting portion upon rotation of the bell member, comprising a substantially disk-shaped element including a tapped central boss and an integral annular skirt, the diameter of the skirt being such as to 4 provide an interference fit in relation to the inner diameter of the bell-shaped member, the upper surface of said skirt abuts the inner surface of said annular face, and said boss projects outwardly of said bore.

2. The improvement as defined in claim 1 wherein said upper annular face includes a downwardly projecting flange integral with the inner periphery of the face, said stamping being located in spaced relation to the face and said flange.

3. The improvement as defined in claim .1 wherein said downwardly projecting flange is of suflicient depth to at least span adjacent crests of threads on the threaded chair post.

4. In a chair having a chair base, a threaded chair post carried by the base, and a seat mounted on the top end of the post, means for effecting up and down adjustment of the chair post relative to floor level comprising:

a bell having an upper annular face and a cylindrical side wall; a central bore through said face through which the upper end of the post projects, said bore having an integrally formed flange of a depth to span adjacent crests of the threads of the chair post; and a central support member mounted within the bell and secured to the cylindrical Wall, said central support member having a threaded hole co-axial with the central bore whereby the support member is mounted on the threaded chair post for up and down adjustment by rotation of said bell.

5. The improvement as defined in claim 4 wherein said central support member comprises a substantially diskshaped element including the tapped central 'boss and an integral annular skirt, the diameter of the skirt being such as to provide an interference fit between the inner diameter of the bell and the annular skirt.

6. The improvement as defined in claim 5 wherein the upper surface of said skirt abuts the inner surface of said annular face, and said boss projects outwardly of said bore.

References Cited UNITED STATES PATENTS 3,151,830 10/1964 Giacomini 248-l88.7 3,161,396 12/1964 Anderson 248405 CHANCELLOR E. HARRIS, Primary Examiner. 

